Pneumatic carrier system



Jan. 4, 1966 w. F. JOY 3,227,396

PNEUMATIC CARRIER SYSTEM Filed Jan. 51, 1964 s Sheets-Sheet 1 FIG.1

ww W** W;

I I 4 INVENTOR. William F. Joy BY [XX/1W Jan. 4, 1966 w. F. JOY 3,227,396

PNEUMATIC CARRIER SYSTEM Filed Jan. 31, 1964 3 Sheets-Sheet 2 FIG. 2 1

63 I I6 3 62 21 l INVENTOR.

William E Joy W M W Attys.

United States Patent 3,227,396 PNEUMATIC CARRIER SYSTEM William F. Joy, Mount Prospect, Ill., assignor to The Powers Regulator Co., Skokie, Ill., a corporation of Illinois Filed Jan. 31, 1964, Ser. No. 341,603 Claims. (Cl. 243-16) This invention relates to the control of the path de fining instrumentalities employed in a multi-loop pneumatic tube system.

Multi-loop pneumatic tube systems are being used in countless industrial, commercial and institutional applications. In these and other applications, the multi-loop systems are designed to effect the transmission of information or message carriers from a variety of points of origin to various remote destinations.

the controlled and selective actuation of the path defining instrumentalities employed in a multi-loop pneumatic tube system. i

It is a further object of the present invention to provide an improved control circuit for a multi-loop pneumatic tube system, which control circuit facilitates the substantially simultaneous dispatch of a plurality of information carriers to various remote destination points through separate loops of the system.

An additional object of the present invention is to provide a method of and circuit for controlling a multiloop pneumatic tube system whereby the simultaneous transmission of information carriers through all loops of the system can be effected, while at the same time assuring that a carrier being dispatched through any one loop reaches the desired destination before subsequent carriers are shunted through that same loop.

A more finite object of the present invention is to provide an improved control circuit for a multi-loop pneumatic tube system, which circuit is relatively low in cost, efficient in operation, and employs a minimum number of components to reliably eifectthe transmission of information carriers to any of a plurality of destinations notwithstanding the number of loops involved.

Other objects and advantages of thepresent invention will become apparent from the following detailed de scription of one preferred embodiment thereof, particularly when considered in conjunction with the accompanying drawings, wherein:

FIGURE 1 diagrammatically represents a portion of a typical multi-loop pneumatic tube system with which the circuit of the present invention might be employed and which can be reliably controlled pursuant to the method of the present invention;

FIGURE 2 is a schematic representation of one portion of the control circuit of the present invention;

FIGURE 3 is a schematic illustration of the remaining portion of one preferred embodiment of the control circuit; and i 5 FIGURE 4 depicts the proper arrangement of FIGS. 2 and 3. t i

As generally outlined above, the present invention is directed to an improved method of and circuit for controlling a multi-loop pneumatic tube system. Basically,

both the method and the control circuit of the present invention contemplate the controlled actuation of the path defining instrumentalities employed in the system so that a plurality of information carriers can be suitably dispatched to desired destination points through the multiple loops.

The general nature of the invention and the manner in which the controlled actuation of the path defining instrumentalities of a multi-loop pneumatic tube system is effected pursuant thereto will best be understood from a consideration of FIGURE 1. Although this figure diagrammatically illustrates the distribution portion of a three loop-three station per lodp system, it should be understood that the present invention can be applied to substantially any multiple loop system notwithstanding the number of loops or the number of stations per loop. Therefore, although the following description is directed to a three loop-three station per loop arrangement, this is in no way a limitation on the applicability of the invention to other systems.

Referring now to FIGURE 1, there is shown a block representation of a control exchange or spacer unit generally designated by the numeral 10. As shown, a plurality of dispatch tubes 11 (i.e. three in the illustrated embodiment) are connected to the spacer 10 so as to feed coded information carriers thereto from conventional input stations (not shown). In a conventional manner and when appropriately actuated, the spacer unit 10 functions to etfect the sorting and/ or interchanging of carriers that are supplied from the dispatch tubes 11 and selectively directs the information carriers to a loop selector 12. The loop selector 12 shunts the information carriers to the desired receiving tube 13 and ultimately to the appropriate remote station 14 (i.e. the destination point) through a station selector unit 15 that is provided in each of the three loops.

In accordance with the present invention, the spacer 10 is preferably provided with responsive means (e.g. suitable switches) which senses the presence of one or more coded information carriers in the inlet tubes (not shown) of the spacer unit. Preferably, the responsive means also provides signal information that is derived from the coded information carriers and which is indicative of the particular receiving tube 13 and remote station 14 to which the carrier or carriers are to be directed. In this connection, the signal information derived from the sensing means is fed to the control circuit of the present invention which is generally designated by the numeral 20.

In response to this signal information, which information corresponds to that coded on the carrier or carriers present in the inlet tubes of the spacer unit 10, the control circuit 20 is selectively rendered effective to actuate the various path defining instrumentalities associated with the system. That is, the control circuit 20, in response to the coded carrier information, actuates the loop selector 12 so that carriers discharged from the spacer unit 10 are shunted to the appropriate receiving tube 13. The control circuit also operates a release mechanism 16 that is associated with the spacer unit 10 so that a carrier is discharged from the spacer unit and fed to and through the remote station '14 as generally described above. After the dispatch of this carrier is initiated, other carriers are precluded from being dispatched through this same loop until such time as the first carrier arrives at the selected station 14. When this occurs, a signal is produced which indicates that this loop is once again free to receive another carrier which is to be transmitted to one of the remote stations 14 with which the loop communicates.

Notwithstanding the fact that one loop is transiently precluded from dispatching additional carriers as long as one carrier is being transmitted therethrough, the other loops of the system are free to receive other carriers. In this connection, the control circuit 20 responds to coded information on carriers that areto be fed to other of the loops and, in'accordance with the invention, actuates the spacer unit '10 and other instrumentalities of the system to define dispatch paths to the designated remote stations 14 with which these other loops communicate.

-If a plurality of carriers arrive at the spacer substantially simultaneously, with one or more'of these carriers being designated for transmission through a then active loop (i.e. a loop through which a carrier is then being dispatched), the control circuit responds to and senses the presence of each of these carriers. However, the control circuit will successively dispatch only those carriers which are designated for remote stations associated with then inactive loops. As each formerly active loop is freed to effect the dispatch of additional carriers, the control circuit will actuate the release mechanism 16 and other instrumentalities so that carriers which were transiently held in the spacer unit can then be sequentially dispatched to the desired destination.

The method of the present invention specifically contemplates the performance of the various controlled operations outlined above independent of the particular type of control circuit employed with the multi-loop pneumatic tube system, although the preferred embodiment of the control circuit typifies additional novel aspects of the invention in the form of control circuitry. However, before proceeding with a detailed description of the novel control circuit 20, it should be pointed out that the spacer 10, release mechanism 16, and the loop and station selector units do not, per se, form a part of the invention. Therefore, these instrumentalities, which supply signals to and are controlled by the circuit 20 in accordance with the invention as outlined above, can be any of a variety of well known and/or commercially available devices.

Additionally, a variety of information carrier constructions are presently employed in pneumatic tube systems, and the nature of the carriers which are coded to provide station destination signal information is not critical. The only requirement which 'must be met by any of these components to insure the realization of the benefits of the invention and the satisfactory functioning of the control circuit when utilized therewith is that these components be capable of either responding to or creating the actuating signals (e.g. switch closures) hereinafter described.

To insure a clear understanding of the invention, the following detailed description is directed primarily to a preferred embodiment of a control circuit constructed in accordance therewith. The control circuit is described when utilized with a spacer unit 10 including sensing means that responds to coded carrier information in the form of suitably spaced and electrically connected metallic bands. That is, the sensing means is preferably a plurality of spring biased switch contacts that are located on the inner walls of the inlet tubes (not shown) "of the spacer unit wh'ereat the information carriers are maintained until such time as the loop selector 12 andrelease mechanism 16 are actuated to initiate the dispatch'of the carriers through the system. However, it should be understood that the control circuit might also be employed with sensing means in the form of coils or reed switches that respond to spaced-apart magnetic elements positioned onthe carriers.

Referring specifically to FIGS. 2 and 3, when arranged as shown in FIG. 4, the numeral 21 designates those switch contacts of the ensing means that indicate the presence of carriers in any one of the inlet tubes of the spacer unit 10. The numeral 22 (FIG. 2) identifies those contacts of the sensing means that supply electrical signals through the coded information carriers depicted by the dashed rectangle 23 and to the control circuit 20, which signals are indicative of the loop (i.e. the tube 13) through which and the remote station 14 to which each of the carriers is to be dispatched.

For purposes of the following description, it will be assumed that three information carriers are substantially simultaneously fed to the three inlet tubes (not shown) provided in the spacer unit 10. Further, it will be assumed that the information carrier which is delivered to the first inlet tube of the spacer unit, thereby actuating the switch contact 21a, is coded so as to be dispatched through the first receiving tube 13 and to the first of the remote stations 14 with which this tube communicates.

In this connection, the control circuit of the present invention preferably employs a conventional stepping switch 25 which controls the operation of four sets of stepping switch contacts 25a, 25b, 25c and 25d as well as an interrupting or resetting switch contact 25c, as hereinafter described in detail. The stepping switch contacts 25a supply the initial operating potential to the control circuit in response to the actuation of the sensing contacts 21 by the introduction of one or more information carriers to the spacer unit It). The contacts 25b constitute a portion of a circuit which provides loop destination signal information as derived from the car- 'riers 23. The contacts 25c form a portion of a circuit that provides station destination signal information as derived from the carriers 23. Finally, the contacts 25d form a portion of an energizing circuit for the necessary components of the release mechanism '16 which are actuated to dispatch a carrier to the desired destination subsequent to the time that the loop and station destination signal information has been derived from that carrier.

Assuming that the wiper arms of the stepping switch '25 have assumed the positions illustrated in FIGURE 2 after the information carriers have located in the inlet tubes of the spacer unit 10 (i.e. in engagement with the first contact of each set), the operation of the control circuit 20 is initiated. More particularly, the introduction of an information carrier to the first of the inlet tubes effects the closure of the switch contact 21a 50 that energizing potential is supplied therethrough to a main supply conductor 27 from one terminal 24 of a suitable source of potential (not shown).

In this connection, the potential supplied from the terminal '24 is fed through the normally closed contact 26a of a time delay relay 26 and through an isolating diode rectifier 23 to a conductor 29. This potential is then fed to the main supply conductor 27 through a circuit defined by the carrier actuated switch 211:, the first contact of the set 25a, the wiper arm engaging this contact, and a normally closed contact 31a of an interrupter relay 31, the function of which will hereinafter be described in detail.

During the interval that potential is supplied to the conductor 27 through the normally closed contact 26a, a capacitor 32, which is connectedbetween a conductor 33'and ground, buildsup a charge, i.e. a voltage is developed thereacross. This voltage insures the continued operation of the control circuit during the time that the switch'arm of the contact 26a swings from the normally closed position to supply energizing potential to a conductor 34 in response to the energization of the time delay relay 26. Obviously, the capacitor 32 can be eliminated from the control circuit 20 if the time delay relay contact 26a is selected to be of the make before break type.

As shown, the conductor 33 isjoined to the anode of the rectifier 28 as well as tothe anodes of diodes 35 and 36, which are connected in parallel with the rectifier 28 and to the carrier actuated switch contacts 21b and 21c through the conductors 37 and 38, respectively. These last mentioned circuits supply energizing potential to the control circuit 29 'in response to carriers being introduced to the other inlet tubes (not shown) of the spacer 10. H

Having assumed that the stepping switch has been actuated so that the wiper arms are located as shown in FIG. 2, the normally closed resetting switch contact 25c will be advanced to an open position. Therefore, energizing potential supplied from .the switch contacts 21 and through one or more parallelly connected rectifiers 39, 40 and 41 is maintained on a conductor 42 but is not supplied to the stepping switch 125. As hereinafter described in detail, the potential established on the conductor 42 serves both to eifect the desired operation of .the stepping switch 25 and to render the time delay circuit, including the relay 26, effective.

With these initial circuit conditions established and with energizing potential applied to the main supply conductor 27, signal information is fed to the instrumentality energizing portions of the control circuit 20 as dictated by the information codedon the carrier within the first inlet tube. Consistent with the foregoing assumption that this carrier is coded for dispatch to the first loop of the three loop system and the first station with which this loop communicates, the potential established on the conductor 27 effects the sequential energization of a loop selector control relay 46 (FIGURE 2) and a station selector control relay 47 (FIGURE 3).

More particularly, energizing potential supplied to the conductor 27 is fed through a normally closed contact 43a of a control relay 43 and through the wiper arm associated with the stepping switch contacts 25b. The latter contacts of the stepping switch 25 supply potential to appropriate ones of the spring biased switch contacts (not shown) locatedon the inner wall of the first inlet tube and this potential is applied to the control portion of the circuit 20 through the electrically connected metallic bands located on the carrier. That is, the energizing potential is fed through the spring biased switch contacts and metallic bands to a conductor 51a, thereby initiating the operation of the control portion of the circuit 20.

In this connection and as shown in FIGURE 2, the conductor 51a is connected to one side of the loop selector control relay 46. This connecting circuit is defined by another normally closed contact 43b of the control relay 43, a conductor 52, a normally closed contact 53a of a busy relay 53, which is associated with the station selector control means of the first loop, and a conductor 54. Since the other side of the loop selector control relay 46 is grounded, the application of energizing potential to this relay through the circuit described above results in the energization thereof and the closure of the normally open contacts 46a through 46g that are associated therewith.

The closure of the contact 46d provides a holding circuit for the relay 46 by supplying energizing potential thereto through a conductor 55 and from a conductor 56 that is connected directly to the supply conductor 27. The closure of the contacts 46b, 46c and 46d results in each of the station-selector control relays (i.e. the relay .47, a relay 57 and a relay 58) being conditioned for energization. However, only one of these relays is actually energize-d to dictate the station to which the carrier being fed through the first loop is to be dispatched, and even this one relay (i.e. the relay 47 pursuant to the assumption outlined above) is not energized until after. energization of the control relay 43 is eifected in response to the closure of the normally open contact 46c. In this connection, the contact 46c, when closed in response to the aforedescribed energization of the loop selector 46,

supplies energizing potential to the control relay 43 from the conductor 56.

Before the control relay 43 becomes energized to actuate the contacts 43a-43f associated therewith, the contacts 467 and 46g are also closed by the energization of the.

loop selector relay 46. The closure of the contact 46] provides a ground for and immediately effects the energization of the appropn'ate component 12a of the loop selector mechanism 12 (i.e. the other side of this component being connected to another terminal of the external source). Accordingly, a discharge path for the carrier is defined from the spacer unit 10 to the first of the loops. Simultaneously therewith, the closure of the contact 46g conditions the appropriate component 16a of the release mechanism 16 for energization, which energization is etfected when the control relay 43 is energized to close the normally open contact 43 Briefly summarizing the operation of the circuit 20 in response to the energization of the relay 46 will be of benefit in understanding the sequential operation of the path defining instrumentalities of the pneumatic tube system. That is, when the relay 47 is energized and the contact 46 closed, the loop selector 12 (i.e. the component 12a thereof) is immediately actuated to define a transmission path from the spacer unit 10 to the appropriate loop (i.e. the first loop in accordance with the assumptions set forth above). Almost immediately after this operation is completed and as a result of the energization of the control relay 43 due to the closure of the contact 46e, the contact 43f is closed to supply energizing potential from a terminal 59 of the external source to the appropriate component 16a of the release mechanism 16. This component 16a, which is actuated to allow the carrier in the first of the inlet tubes to be discharged from the spacer 10, is previously conditioned for energization by the closure of the loop selector relay contact 46g so that a complete path for energizing current is completed from ground through the contact 46g, the wiper arm of the set of contacts 25d, and the contact 43f to the terminal 59.

In addition to effecting these operations, the energization of the relays 43 and 46 also provides energizing potential to the time delay circuit including the relay 26, to thereby condition the entire control circuit 20 for the termination of the cycle of operation then in progress. Furthermore, these relays elfect the actuation of the appropriate component 15a of the station selector mecha nism 15.

More particularly, the closure of the control relay contact 430 results in energizing potential being supplied from the conductor 42 to a con-ductor 61 in the time delay circuit. As a result of energizing potential being supplied to this conductor, the time delay relay26 is energized to provide a parallel holding circuit that main-, tains energizing potential on the main supply conductor 27 and on the conductor 56 even after the carrier actuated switch contact 21a is opened as a result of the dispatch of the carrier from the first of the inlet tubes.

That is, when energizing potential is applied to the conductor 61, a path for current flow is completed from ground through the time delay relay 26 and a current limiting resistor 62 so that the relay 26 becomes energized. As previously described, energization of the relay 26 etfects the actuation of the contact 26a to the alternate, normally open position. When in this position the contact 26a provides energizing potential from the terminal 24 ofthe external source and through the conductor 34 to the conductors 27 and 56. A resistor-capacitor network 63, which is connected in parallel with the serially connected time delay relay 26 and current limiting resistor 62, includes a capacitor 64 that is charged in a conven-- tional manner when energizing potential is applied to the conductor 61. As more fully hereinafter described, the build-up of charge on the capacitor 64 (i.e. the voltage developed thereacross) maintains the relay 26 in an energized state even after thecontrol relay contact 43c returns to the normally open position subsequent to the discharge of the carrier from the inlet tube.

The energization of the control relay 43 that effects the closure of the contact 430 also results in relay contact 43a (FIG. 2) being shifted from the normal position to an alternate position. This shifting of the contact 43a to the alternate position insures that the time delay relay 26 is maintained in anener-gized state and that the time delay cycle (i.e. the discharge of the capacitor 64) is not initiated until after the carrier is discharged from the inlet tube. That is, since the shifting of the time delay relay contact 26a results in potential being supplied to the contact 43a from the terminal 24 through the conductors 34 and 27. This same voltage is supplied to the conductor 42 through the appropriate one of a plurality of diodes 65a, 65b and 650 that are connected in series with conductors 29, 37 and 38, respectively.

More particularly, potential supplied to the contact 43a, after the shifting of the time delay relay contact 26a is fed through the wiper arm for the set of contacts 250 and to the first of these contacts. This potential is then supplied to conductor 61 through a circuit defined by the diode 65a, the conductor 29, the switch contact 21a, the diode 39, the conductor 42 and the now closed control relay contact 430.

The potential supplied tothe first of the contacts 25c through the shifted contact 43a also effects the energization of appropriate station selector component a. In this connection, the voltage established on this stepping switch contact is in turn supplied to the station selector control relay circuitry through the appropriate ones of the spring biased contacts 22 and the electrically connected metallic bands on the carrier located in the first of the inlet tubes. Inasmuch as a finite time interval exists between the actuation of the control relay contacts 4361-43f and the energization of the appropriate component 16a of the release mechanism 16, this station destination information is supplied to the appropriate station selector control relay circuitry before the carrier is freed from the spacer 10.

As with the loop destination information, the station information is derived from the application of energizing potential to an appropriate one of the conductors 51a, 51b or .52c subsequent to the time that the contacts 43b, 43d and 432 are shifted to their alternate positions in response to the energization of the control relay 43 Specifically, energizing potential applied to the conductor 51a is fed through the control relay contact 4311, the contact 4611 and through a conductor 66 to the ungrounded side of the relay 47. As shown in FIG. 3, the relay 47 has the other side thereof connected to ground through a conductor 67 and a series arrangement of microswitch contacts 68a, 68b and 68c.

Upon being energized, the relay 47 closes a contact 47a that completes a holding circuit for this relay from a terminal 69. In addition, the relay 47 closes a normally open contact 47b so that energizing potential is supplied to the appropriate station selector component 15a. The path for energizing current to the component 15a of the station selector mechanism 15 is provided from a terminal 71, through the normally closed contact 47b and through a conductor 68 to one side of this component, the other side thereof being grounded as shown. When actuated, the component 15a insures that the carrier released from the spacer and being directed through the first loop is shunted to the first of the three stations with which this loop communicates.

The relay 47 also effects the closure of a normally open contact 47c thereby supplying energizing potential from a terminal 72 to the busy relay 53 which is also grounded through the conductor 67 and the series arrangement of microswitch contacts 68a, 68b and 680. Energization of the relay 53 and the closure of the contacts 53a and 531) set up conditions within the control circuit whereby the dispatch of another carrier to the first loop is precluded until the carrier in transit has reached the remote station 14 as indicated by the opening of the microswitch contact (i.e. the grounding circuit for the relays 47 and 53) of the microswitch located in the carrier receptacle at this station.

However, before considering the selective and transient loop blocking operations effected by the busy relay 53 in conjunction with the stepping switch 25, the response of the control circuit to the discharge of the carrier from the first inlet tube (i.e. the opening of the contact 21a) and the shifting of the contact 53a will be described.

In this connection, energization of the busy relay 53 and the shifting of the contact 53a completes an energizing circuit for the interrupter relay 31. That is, energizing potential is applied to this relay from the conductor 52 and through a conductor 72. When energized, the relay 31 actautes the normally closed contact 31a so as to interrupt one of the parallel energizing paths for the stepping switch 25, the stepping switch being maintained in an energized state by potential supplied thereto from the'terminal 24, through the time delay relay contact 26a, and through the conductors 34 and 27.

This alternate energizing circuit for the stepping switch 25 is conditioned for interruption, however, upon the transmission of the carrier from the inlet tube of the spacer unit and through the path defined in response to the actuation of the components previously described. That is, when the component 16a of the release mechanism is actuated to allow the carriers to drop from the inlet tube, the carrier actuated, sensing switch contact 21a opens so as to cut-off the supply of energizing current to the time delay relay 26.

However, rather than being immediately deenergized so as toterminate the cycle of operation, the time delay relay is retained in its operative position (i.e. with the contact 26a shifted to supply potential to the conductor .27) for a preselected period of time by the charge on the capacitor 64. That is, the relay 26 is maintained energized only long enough to insure that the carrier from which the path defining information has been derived, is discharged from the spacer 10 and into the desired loop. When the relay 26 is deenergized (i.e. due to the discharge of the capacitor 64 to ground through the resistor 62 and relay 26), the contact 26a returns to the normally open position thereby removing energizing potential from the conductors 27 and 56. When this occurs, the relays 43 and 46 are deenergized so that the contacts associated therewith return to their normal positions, and this effects the deactuation of the loop selector component 12a and release mechanism component 16a. Accordingly, the control circuit 20 is conditioned to effect the dispatch of other carriers from the inlet tubes of the spacer unit 10 through the other of the loops and ultimately to the remote stations 14 with which these other loops communicate.

The aforedescribed deenergization of the relays 43 and 46 and the conditioning of the control circuit 20 to effect the sequential dispatch of other carriers to other of the loops also causes the relay 31 to be deenergized due to energizing potential being removed from the conductor 52. In addition, the removal of potential from the conductor 27 results in the stepping switch 25 being deenergized so that the interrupter contact 252 returns to its normally closed position.

Assuming that other carriers are present in the inlet tubes of the spacer unit 10 so as to cause the closure of the sensing switch contacts 21b and 21c, energizing potential is then supplied to the stepping switch 25 through the rectifiers 40 and 41 and the contact 252. Accordingly and in a conventional manner, the stepping switch 25 is again energized so that the wiper arms of each set of contacts 25a-25d are advanced from engagement with the first contact and into engagement with the second contact. At the same time, the interrupter contact 25s is opened. Since the carrier sensing switch .contact 21!; is closed by aazzaae a 9 a carrier in. the second spacer inlet tube of the spacer 10, the stepping switch 25 is maintained in an energized state and does not immediately advance to the next position.

Assuming further that the carrier within this second inlet tube is coded for dispatch to the second loop and the second station with which this loop communicates, ener-l gizing potential distributed through the coded metallic bands on the carrier actuates appropriate components of the control circuit in a manner corresponding to tha-t previously described. I More particularly and consistent with the foregoing description, the control relay 43 and the loop selector relay 46' are energized to actuate the instrumentalities that define the transmission path to and through the second loop (i.e. the loop selector component 12b) and the release component 16b. Similarly, a station selector control relay 57' is energized to effect the actuation of the appropriate station selector component b. i i

After this carrier is dispatched from the second inlet tube of the spacer unit, the control circuit is again conditioned for subsequent cycles of operation. That is, the

stepping switch 25 advances the wiper arms to engage the next succeeding contact of each of the sets 25a-25d.

. Assuming that a carrier-is located in the third inlet tube so as to close the contact 21s, the control circuit again responds to direct this carrier to the desired destination, if this destination does not require use of a then active loop. If, for example, the carrier Within this third inlet tube is coded for dispatch to the third loop and the third station with which this loop communicates, the loop selector relay 46" and-station selector relay 58" are energized and the previouslygdcscrirbed cycle of operation is repeated to actuate the appropriate path defining instrumentalitie's 12c, 16c and 150'.

- Each ,time. a carrier is dispatched through one of the loops, the busy relay (i.e. the relay 53,53 or 53") associated therewith precludes a second carrierfrom being introduced to and dispatched through that same loop until the first carrier-reaches the appropriate station 14. However, the -transmission of other carriers .to other of the then inactive loops is inno way inhibited.

.Thislatter aspect of the'control circuit is alsobe'st illustrated byway of example: Assumingthat the second loop oftheillustrated systemis dispatching a carrier therethrough, the busy relay 53' is energized and ismaintained in an energized state by the closure of the contact 53b. If the next carrier located in the spacer unit is similarly coded for transmission through the second loop, the control circuit will skip this carrier and. go on tothe next. That is, energizing potential is supplied through the conductor 51b" and through the conductor 52' to the contact 53a. Since this loop is .active, the contact 53a supplies this potential di-rectly to the. conductor 72 to cause the relay 31 to be energized. Accordingly, the relay contact 31a is opened, the stepping switch is deenergized, and the cycle repeats itself by dispatching another carrier to a then inactive loop. It will be noted that all of these operations occur at the beginning of a cycle of operation when the only path for energizing current to the stepping switch is through the contact 31a and prior to the time that the master control relay 43 is energized.

As long as the busy relays (i.e. the relays 53, 53' and 53") are energized, the corresponding loop is effectively isolated from the spacer unit 10. However, when a carrier that has been dispatched through a loop has reached the selected remote station 14, a corresponding one of the microswitch contacts (e.g. 68a, 68b or 680) will be actuated and opened so that the then energized station selector relay and busy relay become deenergized, and the loop is then free to receive other carriers.

From the foregoing description, it will be appreciated that the present invention provides an improved method of and circuit for effecting the controlled and selective actuation of the path defining instrumentalities of a multiloop pneumatic tube system. The control circuit is readily adaptable for use with substantially any such system, notwithstanding the number of loops or stations involved, and requires only a minimal number of circuit components. An additional advantageous aspect of the present invention is that substantially all of the control circuit components can be maintained at one physical location in the pneumatic tube system, i.e. adjacent the spacer unit 10. Only those components that effect the actuation of the station selector mechanism components need he remote from the other components of the control circuit. This latter aspect of the circuit need not, however, present any problem since in certain applications it might be desirable to eliminate the station selector control components from the overall control circuit. That is, it may be desirable to eliminate the station selector control components and rely on other means for effecting the selection of the appropriate station at a remote location. To this end, control circuits such as those disclosed and claimed.

in the co-pending application of the common assignee,

; Serial No.295,126 which was filed on July 15, 1963, might be utilized in conjunction with the control circuit to derive information from the coded carriers after dispatch intothe appropriate loop so that the desired station selector component can be actuated.

It willbe appreciated that the various components designated 'by like but primed or double primed numerals carry out identical functions within their given loop and these functions are performed in response to information coded on the carriers Within the spacer 10 as previously described. Moreover, it will :be obvious to those skilled in the art that such components as the diode rectifiers that shunt the various relays and minimize inductive effects are utilized in a typical manner inthe illustrated circuit; therefore the function of each of these conventional components has not been specifically described nor has each of these components been designated with a particular identifying numeral.

. It will be further appreciated that various modifications of the circuitry specifically disclosed herein might be de vised by one skilled in the art Without departing from the invention, various features of which are set forth in they accompanying claims. 4 What is claimed is:

1. A circuit for controlling the selective actuation of the path defining instrumentalities employed in a multiloop and station pneumatic tube system including apparatus for receiving a plurality of carriers, apparatus for defining a path from the receiving apparatus to a selected one-of the loops, apparatus for dispatching carriers from the receiving apparatus and through selected ones of the loops, and apparatus for directing a carrier being dispatched through one of the loops to a selected one of the stations With which the loop communicates; which circuit comprises means for sensing the presence of carriers withi in the receiving apparatus; first circuit means electrically connected to said sensing means and actuated in response to the sensing of a carrier Within the receiving apparatus so as to complete an energizing circuit for the loop defining apparatus of the pneumatic tube system; second circuit means electrically connected to said first circuit means and rendered effective in response to the actuation thereof so as to condition the station directing apparatus for energization; third circuit means electrically connected to said first and second circuit means and responsive to the actuation thereof so as to effect the energization of the carrier dispatching apparatus and stat-ion directing apparatus of the system; and a timing circuit electrically connected to said sensing means and actuated in response to the actuation of said second circuit means for maintaining the control circuit in an operative condition for a period corresponding at least to the time required to dispatch a carrier from the carrier receiving apparatus and to the selected loop.

2. Control means for a multi-loop and station pneumatic tube system that effects the transmission of coded information carriers through selected ones of the loops of the system and to selected ones of the remote stations with which the loops communicate; which control means comprises means adapted to receive and transiently maintain a plurality of the coded information carriers therein; means associated with said receiving means for sensing the presence of carriers therein, means electrically connected to said last mentioned means for deriving the coded information from the carriers, first means responsive to signals corresponding to the coded carrier information and rendered effective thereby to define a distribution path from the receiving means and to a selected one of the loops of the system; second, third and fourth responsive means; said second responsive means being actuated in response to the operation of said first responsive means to energize said third and fourth responsive means; said third responsive means effecting the discharge of one of the carriers from said receiving means and to the selected one of the loops; said fourth responsive means defining a dispatch path for the coded carrier from the selected loop and to a selected one of the stations with which the loop communicates and being maintained in an actuated state until the coded carrier has reached the selected station; time delay means energized in response to the actuation of said second responsive means for maintaining said first and second responsive means in an energized state until the coded carrier is dispatched from said receiving means and into the selected one of the loops; and means connected in circuit with and rendered effective by said fourth responsive means so that another carrier is precluded from being dispatched to the same selected loop until the carrier in transit has reached the selected station with which that loop communicates as indicated by the deactuation of said fourth responsive means.

3. A circuit for controlling the selective actuation of the path defining instrumentalities employed in a multiloop and station pneumatic tube system including apparatus for receiving a plurality of carriers, apparatus for defining a path from the receiving apparatus to a selected one of the loops, and apparatus for dispatching carriers from the receiving apparatus and through selected ones of the loops; which circuit comprises means for sensing the presence of carriers within the receiving apparatus; first circuit means electrically connected to said sensing means and actuated in response to the sensing of a carrier within the receiving apparatus so as to complete an energizing circuit for the loop defining apparatus of the pneumatic tube system; second circuit means electrically connected to said first circuit means and responsive to the actuation thereof so as to effect the energization of the carrier dispatching apparatus; and a timing circuit electrically connected to said sensing means and actuated in response to the actuation of said second circuit means for maintaining the control circuit in an operative condition for a period corresponding at least to the time required to dispatch a carrier from the carrier receiving apparatus and to the selected loop.

4. A method of transmitting a plurality of carriers from a distribution location through a multi-loop pneumatic tube system and to various preselected remote destination points; which method comprises sensing the presence of at least one carrier at the distribution location and deriving information indicative of the remote destination point to which said carrier is to be dispatched; defining a dispatch path from the distribution location to a selected one of the loops in accordance with said derived information; advancing the carrier from the distribution location and into the selected loop through the defined path; defining a path for the carrier from the selected loop to a selected destination point with which the loop communicates substantially simultaneously with the advancement of the carrier from the distribution location; and transiently precluding other carriers frombeing dispatched to the same loop until the carrier in transit has been advanced at least a preselected distance toward the selected destination point.

5. A method of sequentially effecting the transmission of a plurality of coded information carriers from a distribution location through a multi-loop and station pneumatic tube system and to various preselected remote destination points; which method comprises receiving and transiently maintaining a plurality of the coded information carriers at a distribution location; sequentially deriving the coded information from the carriers; defining a first distribution path for one of the carriers from the distribution location and to a selected one of the loops of the system pursuant to at least a portion of the derived information; advancing the one carrier from the distribution location and through the defined distribution path to the selected one of the loops; defining a second distribution path for the carrier from the selected loop and to a selected one of the remote destination points with which the loop communicates pursuant to at least a portion of the derived information; maintaining the first distribution path in the defined condition until the carrier has entered the selected one of the loops; and precluding another carrier from being dispatched to the same selected loop until the carrier in transit has been advanced at least a preselected distance toward the remote destination with which that loop communicates.

References Cited by the Examiner UNITED STATES PATENTS 1,840,394 l/1932. Jennings 243-30 2,710,728 6/ 1955 Halpern 24336 2,970,791 2/ 1961 Hafner. 3,152,681 10/1964 Byrnes 243-16 5 SAMUEL F. COLEMAN, Primary Examiner.

ANDRES H. NIELSEN, Examiner. 

1. A CIRCUIT FOR CONTROLLING THE SELECTIVE ACTUATION OF THE PATH DEFINING INSTRUMENTALITIES EMPLOYED IN A MULTILOOP AND STATION PNEUMATIC TUBE SYSTEM INCLUDING APPARATUS FOR RECEIVING A PLURALITY OF CARRIERS, APPARATUS FOR DEFINING A PATH FROM THE RECEIVING APPARATUS TO A SELECTED ONE OF THE LOOPS, APPARATUS FOR DISPATCHING CARRIERS FROM THE RECEIVING APPARATUS AND THROUGH SELECTED ONES OF THE LOOPS, AND APPARATUS FOR DIRECTING A CARRIER BEING DISPATCHED THROUGH ONE OF THE LOOPS TO A SELECTED ONE OF THE STATIONS WITH WHICH THE LOOP COMMUNICATES; WHICH CIRCUIT COMPRISES MEANS FOR SENSING THE PRESNECE OF CARRIERS WITHIN THE RECECING APPARATUS; FIRST CIRCUIT MEANS ELECTRICALLY CONNECED TO SAID SENSING MEANS AND ACTUATED IN RESPONSE TO THE SENSING OF A CARRIER WITHIN THE RECEIVING APPARATUS SO AS TO COMPLETE AN ENERGIZING CIRCUIT FOR THE LOOP DEFINING APPARATUS OF THE PNEUMATIC TUBE SYSTEM; SECOND CIRCUIT MEANS ELECTRICALLY CONNECTED TO SAID FIRST CIRCUIT MEANS 